Smoking is to be banned in all 860 national parks in NSW, Environment Minister Rob Stokes has announced.

Smoking is to be banned in NSW national parks, the state government has announced.

Environment Minister Rob Stokes said the ban would lessen the risk of bushfires and reduce litter.

Seven billion cigarette butts are dropped in Australia every year and as well as looking unsightly, they contain hazardous chemicals such as arsenic and lead, which can then leach into the environment.

Wildlife can also eat cigarette butts.

Making the announcement on Sunday, Mr Stokes said the ban would apply to picnic areas, campgrounds, beaches, lookouts, walking tracks and national parks roads.

"The NSW government is serious about reducing fire risk and littering in NSW, and this move will reduce litter and help to keep communities safer," he said in a statement.

"We have 860 national parks in NSW which protect our most beautiful and most popular natural areas.

"We want to make sure they are safe and healthy for everyone."

The move comes after Police and Emergency Services Minister Stuart Ayres recently announced that the penalty for littering lighted cigarettes had doubled from $330 to $660.

The fine has also risen from $660 to $1320 if someone discards a lit cigarette on a total fire ban day.

Copyright AAP 2014.